fix: review round 1 — row press after a rename, related reset, dead items on removal, honest Prev/Next

- A press that begins while a field in the row is edited only ends the editing (rowOpen latches it
  at pointerdown); the card layout's row press is now tested.
- A related video reset in the player forgets the session's stored position.
- Removing the playing video passes over known-dead items and steps the way it went.
- Prev/Next off only because of dead items stay focusable and say why (HU/EN).
- The docked bar's scroller leaves room for focus rings.
- A focus-opened About card is not closed by its own scroll into view.
- EN "Clear watch progress" for the video reset, distinct from a page's "Reset view".
- The signed-out title read goes to the page yt-dlp read; the retitle writes are conditional.
- Tests: the cap of three errors, the bar's own Fullscreen, the group glyph, the backfill's reads.

frontend/src/modules/channels/AboutCell.dom.test.tsx

@@ -2,7 +2,8 @@
 //
 // The About cell's card opened the instant a pointer crossed the cell, so scrolling the table over
 // a column of them popped card after card. It waits for the pointer to rest on the cell now, and a
-// scroll puts an open one away.
+// scroll puts an open one away — unless the keyboard's focus opened it, whose own scroll into view
+// would put it away the moment it opened.
 import { describe, it, expect, vi, afterEach, beforeEach } from "vitest";
 import { render, screen, fireEvent, act, cleanup } from "@testing-library/react";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
@@ -66,4 +67,14 @@ describe("AboutCell — the hover card", () => {
     await wait(50);
     expect(card()).toBeNull();
   });
+
+  it("stays when the focus that opened it scrolls its cell into view", async () => {
+    const cell = mount();
+    act(() => cell.focus());
+    await wait(10);
+    expect(card()).not.toBeNull();
+    act(() => void window.dispatchEvent(new Event("scroll")));
+    await wait(50);
+    expect(card()).not.toBeNull();
+  });
 });